Hierarchically structured PVDF/ZnO core-shell nanofibers for self-powered physiological monitoring electronics

Piezoelectric-based wearable electronics promise potential applications in human physiological monitoring for disease prediction, diagnose and rehabilitation. Still, it is a big challenge to fulfill excellent compatibility and precisely monitoring of the complexly subtle physiological signals simultaneously. Here, we prepared a three-dimensional hierarchically interlocked PVDF/ZnO nanofiber-based piezoelectric sensor through epitaxial growing ZnO nano rods (NRs) on the surface of electrospun PVDF nanofibers, which enables the fiber-based physiological monitoring electronics (PME) of well flexibility and high gas permeability. Due to synergistic piezoelectric effect of the effectively deformed interlocked ZnO NRs and the uniformly orientated PVDF nanofibers with high electroactive phase, the sensitivities of PME in both pressing and bending modes have been greatly improved 6 times and 41 times than that of pure PVDF nanofibers respectively. On this basis, the designed PME can precisely detect the complexly subtle physiological signals of respiration, wrist pulse and muscle behavior. Moreover, a sensitive gait recognition system was successfully developed based on PME arrays. Therefore, this proposed fiber-based device provides an alternative strategy to monitor the human subtle physiological signals and demonstrates promising potential in the expanded application of healthcare and clinical diagnosis.